IP SAN vendors claim low cost, high uptime

IP SAN vendors claim low cost, high uptime

New types of IP storage area networks promise to be more affordable than conventional SANs, at least when top-speed access isn't the top priority.

Proponents claim that IP SANs on standard Ethernet networks cost about 20 percent as much as Fibre Channel SANs, with 80 percent of the speed. IP SANs use low-cost Ethernet network cards and commodity hard drives, routers and switches. They follow the emerging Internet Small Computer System Interface standard, or iSCSI.

"Right now, iSCSI is kind of a land grab--everyone is getting into the market," said Jay Masterson, a systems engineer at MPC Computers LLC of Nampa, Idaho, which demonstrated its new IP SAN unit last week at the FOSE trade show in Washington

LeftHand Networks Inc. of Boulder, Colo., demonstrated a design that lets the systems administrator configure a SAN in building-block fashion. Each storage module comes with its own motherboard and processor to store 640G, 1T or 2T of data.

As storage needs grow, the administrator adds more boxes, said David Bangs, sales vice president at LeftHand.

"Most other storage architectures will see performance decline with added capacity, because of the single network connection. Reliability also falls off because the capacity is behind a single head or backplane," Bangs said. His company's approach is that "when you add a module, you are adding redundant components--backplanes, motherboards and power supplies."

IT heavyweights emphasized ease of use and low price. Dell Inc.'s AXI100i was developed by EMC Corp. of Hopkington, Mass., which also sells the unit under its own brand. It's designed for offices deploying their first SAN, said Chris Deluzo, enterprise systems consultant for the company's federal unit.

Such offices might now be using direct-attached SCSI storage and would like to move into centralized storage but don't have a lot of money or a lot of applications with high I/O requirements, Deluzo said.

The Dell/EMC unit has 12 drives and scales up to 3T. It can link into 8-unit arrays. A unit costs about $15,000, about half the cost of a conventional SAN, he said.

MPC's $19,999 DataFrame 420 handles 4T spread across up to 16 drives. The DataFrame can use RAID redundancy techniques across different SAN systems, in addition to striping RAID across disks within a single system.

"It has system-level failover," Masterson said. An organization can set up three systems and have each mirror the data of the other two. If one goes down, the data will stay intact on the other systems.

In some cases, IP SANs can serve as an alternative to tape backup. Recovering data from a disk is faster than from tape, though disks don't have the long lifespan of tapes. Copan Systems of Longhorn, Colo., showed a SAN with a large number of redundant disks to extend reliability.

Copan calls its architecture a massive array of redundant disks, or MAID, said Wil Layton, vice president of business development. The company is pitching its Revolution 200T storage system to agencies with large amounts of reference materials or infrequently accessed files. Each cabinet can hold up to 896 drives storing 224T. The company uses virtual tape library software from FalconStor Software Inc. of Melville, N.Y., and can provide either a Fibre Channel or an iSCSI interface.

To extend the life of each disk, Copan's software turns off the disk when its data is not in use. That also cuts power consumption.

"If you leave a light off all the time, the light bulb lasts longer. The same thing happens with disk architecture," Layton said.

The software spins up each disk periodically to ensure it still works, and it also automatically removes data from disks that are starting to fail. System administrators can set regular intervals'-Copan recommends once a year'-to change out faulty disks without incurring downtime.

About the Author

Joab Jackson is the senior technology editor for Government Computer News.

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